Re: [Wien] mBJ for FeO

[John McLeod]

Hello all,

I tried to calculate the electronic structure of FeO using mBJ.

  1. I took the cubic FeO structure, made a 2x2x2 primitive supercell, 
relabeled the Fe sites "1" and "2" to get the appropriate AFM ordering, 
ran sgroup, and obtained a rhombohedral cell with 2 Fe sites and 1 O 
site. This structure looks correct when viewed with VESTA or xcrysden, 
so I think I am using the correct structure.


  2. I run a spin-polarized PBE calculation, initializing the Fe to 
"up" and "down", and the O to "no spin", this converges quickly and 
obtains a zero band gap as expected.


  3. I run an mBJ calculation using PRATT mixing, slowly increasing the 
mixing factor. The energy converges in 20 cycles or so, however the 
charge never converges - it keeps "sloshing" back and forth between the 
two Fe sites. The band gap for this system remains at zero.


In PRL 102 226401 (2009) and mBJ calculation on FeO reports a gap of 
1.82 eV. May I ask Dr. Fabian Tran and/or Dr. Peter Blaha, to obtain 
these results did you:

   1. Perform an AFM calculation or just a spin-polarized calculation?
   2. Perform any sort of structural optimization?
   3. Use PRATT mixing only, or switch back to MSR1?

I also tried this approach with hematite (Fe2O3), obtaining a 
rhombohedral structure with 4 inequivalent Fe sites (as expected), and 
following the same steps I obtained good charge and energy convergence 
in mBJ as well as a reasonably accurate band gap - so I find it a bit 
curious that my approach fails for FeO.


I would greatly appreciate a quick tip on how the original calculations 
in PRL 102 226401 were performed.


Regards,
John McLeod


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Re: [Wien] Issue with different convergence results and QTL-B warnings

[Michał Wojciechowski]

- The execution is always the same. I used the -in1new switch on a copy of the 
case directory to determine the correct energy parameters. For the proper 
calculations I manually changed the energy parameters in case.in1c
- All the in-files are the same (except for the carbon part). So are the struct 
files
- I did not perform relaxation. I'm trying to stick to the original structure 
of the molecule.
- I use RKM=2.0 because the calculations are 3 times faster than for RKM=3.0 
and it turns out that there is no significant difference between results 
(energy, J, MMI, gaps, ...) for RKM=2.0 and 3.0. Also changing RMT or 
k-sampling is unimportant (although for smaller RMT magnetic moments for Cr 
decrease about 0.2 Bohr magnetons). However this is based on my previous 
experience with PBE functional for these structures and it might not be true 
for B3LYP. The reason I use these RMT-s is because I wanted them to be the same 
as in Acta Phys. Pol. A. 127, 407 (2015) and Phys. Rev. B 73, 184431 (2006).
- As for the magnetic moments they are almost constant and definitely hold 
their orientation. The same goes for partial charges - in both approaches they 
are the same.
- Offtop: the relation J = (E_FM - E_AFM)/36 for Cr8 is obtained from a general 
Ising-like magnetic Hamiltonian:
H=sum(J*S_{i}*S_{i+1})
where S are spins of Cr ions, S=+/- 3/2. For 8 Cr this gives 8 interactions 
between neighboring ions and for AFM configuration
H=J * 8 * - 3/2 * 3/2=-18J=E_AFM
and for FM configuration
H=J * 8 * 3/2 *3/2=18J=E_FM
If we take the difference we get
E_FM-E_AFM=18J- -18J=18J+18J=36J


Best Regards
Michał Wojciechowski
PHD student at Institute of Physics
Department of Physics and Astronomy
University of Zielona Góra, Poland


- Oryginalna wiadomość -
Od: "Lyudmila Dobysheva" 
Do: "A Mailing list for WIEN2k users" 
Wysłane: czwartek, 10 grudzień 2015 12:02:08
Temat: Re: [Wien] Issue with different convergence results and QTL-Bwarnings

I am not an expert in B3LYP, so I am writing about only general 
considerations.
The reason may be
1) different execution. For example, you have made, by accident, for the 
final calculation in first case -in1new, in second - usual, without this 
option. Check the executions in dayfile's, :log's, and everywhere where 
this info can be found. And check all parameters. Compare the in-files 
in the whole saved directories.
Though system looks rather symmetric, there are 5 nonequivalent Cr 
atoms. Had you done force relaxation? Is struct files identical in both 
cases? in all four cases?
2) Maybe some parameter doesn't reach convergence, so small variations 
in calculation scheme (starting electron density) gives different 
results. Under suspicion, imho, RKM = 2.0 (as far as I remember, the 
recommendation for H-containing systems is RKM=3), very different RMT
2.40 and 0.83 Bohr for Cr and H, single k point.
3) maybe this exotic scheme of potential gives you really two different 
points? Look in case.scf other parameters, especially magnetic moments 
of Cr's, especially FM states (the difference is largest. For AFM it 
looks for me as not different).
3A) maybe this is a peculiarity of B3LYP scheme, and its iterative 
procedure allows to fix solution in some points that are not real 
minimum. Maybe users with experience with B3LYP can add something about 
this.
3B) Maybe this different solutions are really different minimums due to 
different Cr atoms with differently distributed moments among them.

Offtop:
 > J = (E_FM - E_AFM)/36.
Why 36? There is another number of atoms?

Best wishes
Lyudmila Dobysheva
--
Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci.
426001 Izhevsk, ul.Kirova 132
RUSSIA
--
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Re: [Wien] Correct band gap value

[Muhammad Sajjad]

It looks same (in shape). I selected lattice type F and applied strain.
Only symmetry operations reduce to 16 from 48 (for bulk Si). Also I kept
the volume constant for every value of strain.

On Thu, Dec 10, 2015 at 11:29 AM, Fecher, Gerhard 
wrote:

> Did you check how the Brillouin zone looks like in the tetragonal case
> after you applied the strain ?
> Is your k-path that you used for the xmgrace plot the one that you like to
> have to find the correct gap ?
>
> Ciao
> Gerhard
>
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
>
> 
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry
> Johannes Gutenberg - University
> 55099 Mainz
> and
> Max Planck Institute for Chemical Physics of Solids
> 01187 Dresden
> 
> Von: wien-boun...@zeus.theochem.tuwien.ac.at [
> wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Muhammad Sajjad [
> sajja...@gmail.com]
> Gesendet: Donnerstag, 10. Dezember 2015 09:19
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] Correct band gap value
>
> Manually means I opened the band structure in xmgrace then simply clicked
> on the CBM and the went to the text editor to read the exact lowest value.
> I am simply using Silicon (with 2% strain) and the plot is along W L G X W.
>
> On Thu, Dec 10, 2015 at 10:35 AM, > wrote:
> What does "manually" mean? If it means band structure plotting, then
> probably the VBM and/or CBM is not along the path in the Brillouin zone
> that you chose.
>
> F. Tran
>
>
> On Thu, 10 Dec 2015, Muhammad Sajjad wrote:
>
> I selected 2000 k-points. grep GAP *.scf gives 0.923 eV while manually I
> found VBM at 0.0 eV and CBM at 1.10023 eV. So which one should be correct?
>
> On Thu, Dec 10, 2015 at 12:20 AM, > wrote:
>   If your k-mesh is not dense enough such that there is no k-point
>   at the VBM and/or CBM or close to, then :GAP will be larger than
>   the band gap from a band structure.
>
>   F. Tran
>
>   On Wed, 9 Dec 2015, Muhammad Sajjad wrote:
>
> Dear AllDoes the command "grep GAP *.scf" gives
> correct band gap value? as when I found the bottom
> of conduction band in xmgrace it is higher. (bottom
> of CB is
> read correctly by opening the plot in xmgrace and
> then read the date by editing in text editor).
>
> --
> Kind Regards
> Muhammad Sajjad
> Post Doctoral Fellow
> KAUST, KSA.
>
>
>   ___
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>   SEARCH the MAILING-LIST at:
>
> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>
>
>
>
> --
> Kind Regards
> Muhammad Sajjad
> Post Doctoral Fellow
> KAUST, KSA.
>
>
> ___
> Wien mailing list
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> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
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>
>
>
>
> --
> Kind Regards
> Muhammad Sajjad
> Post Doctoral Fellow
> KAUST, KSA.
> ___
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>



-- 
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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Re: [Wien] Correct band gap value

[Fecher, Gerhard]

Did you check how the Brillouin zone looks like in the tetragonal case after 
you applied the strain ? 
Is your k-path that you used for the xmgrace plot the one that you like to have 
to find the correct gap ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Muhammad Sajjad 
[sajja...@gmail.com]
Gesendet: Donnerstag, 10. Dezember 2015 09:19
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] Correct band gap value

Manually means I opened the band structure in xmgrace then simply clicked on 
the CBM and the went to the text editor to read the exact lowest value. I am 
simply using Silicon (with 2% strain) and the plot is along W L G X W.

On Thu, Dec 10, 2015 at 10:35 AM, 
> wrote:
What does "manually" mean? If it means band structure plotting, then
probably the VBM and/or CBM is not along the path in the Brillouin zone
that you chose.

F. Tran


On Thu, 10 Dec 2015, Muhammad Sajjad wrote:

I selected 2000 k-points. grep GAP *.scf gives 0.923 eV while manually I
found VBM at 0.0 eV and CBM at 1.10023 eV. So which one should be correct?

On Thu, Dec 10, 2015 at 12:20 AM, 
> wrote:
  If your k-mesh is not dense enough such that there is no k-point
  at the VBM and/or CBM or close to, then :GAP will be larger than
  the band gap from a band structure.

  F. Tran

  On Wed, 9 Dec 2015, Muhammad Sajjad wrote:

Dear AllDoes the command "grep GAP *.scf" gives
correct band gap value? as when I found the bottom
of conduction band in xmgrace it is higher. (bottom
of CB is
read correctly by opening the plot in xmgrace and
then read the date by editing in text editor).

--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.


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--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.


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--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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Re: [Wien] Correct band gap value

[Muhammad Sajjad]

Here is the structure with 2% tensile strain.
SILICON

F   LATTICE,NONEQUIV.ATOMS:  1

MODE OF CALC=RELA unit=ang

 10.511739 10.204090 10.204090 90.00 90.00 90.00

ATOM  -1: X=0.1250 Y=0.1250 Z=0.1250
  MULT= 2  ISPLIT=-2
  -1: X=0.8750 Y=0.8750 Z=0.8750
Si NPT=  781  R0=0.0001 RMT=2.2200   Z: 14.0

LOCAL ROT MATRIX:0.000 0.000 1.000
 1.000 0.000 0.000
 0.000 1.000 0.000
  16  NUMBER OF SYMMETRY OPERATIONS

On Thu, Dec 10, 2015 at 12:05 PM, Muhammad Sajjad 
wrote:

> It looks same (in shape). I selected lattice type F and applied strain.
> Only symmetry operations reduce to 16 from 48 (for bulk Si). Also I kept
> the volume constant for every value of strain.
>
> On Thu, Dec 10, 2015 at 11:29 AM, Fecher, Gerhard 
> wrote:
>
>> Did you check how the Brillouin zone looks like in the tetragonal case
>> after you applied the strain ?
>> Is your k-path that you used for the xmgrace plot the one that you like
>> to have to find the correct gap ?
>>
>> Ciao
>> Gerhard
>>
>> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
>> "I think the problem, to be quite honest with you,
>> is that you have never actually known what the question is."
>>
>> 
>> Dr. Gerhard H. Fecher
>> Institut of Inorganic and Analytical Chemistry
>> Johannes Gutenberg - University
>> 55099 Mainz
>> and
>> Max Planck Institute for Chemical Physics of Solids
>> 01187 Dresden
>> 
>> Von: wien-boun...@zeus.theochem.tuwien.ac.at [
>> wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Muhammad Sajjad [
>> sajja...@gmail.com]
>> Gesendet: Donnerstag, 10. Dezember 2015 09:19
>> An: A Mailing list for WIEN2k users
>> Betreff: Re: [Wien] Correct band gap value
>>
>> Manually means I opened the band structure in xmgrace then simply clicked
>> on the CBM and the went to the text editor to read the exact lowest value.
>> I am simply using Silicon (with 2% strain) and the plot is along W L G X W.
>>
>> On Thu, Dec 10, 2015 at 10:35 AM,  t...@theochem.tuwien.ac.at>> wrote:
>> What does "manually" mean? If it means band structure plotting, then
>> probably the VBM and/or CBM is not along the path in the Brillouin zone
>> that you chose.
>>
>> F. Tran
>>
>>
>> On Thu, 10 Dec 2015, Muhammad Sajjad wrote:
>>
>> I selected 2000 k-points. grep GAP *.scf gives 0.923 eV while manually I
>> found VBM at 0.0 eV and CBM at 1.10023 eV. So which one should be correct?
>>
>> On Thu, Dec 10, 2015 at 12:20 AM,  t...@theochem.tuwien.ac.at>> wrote:
>>   If your k-mesh is not dense enough such that there is no k-point
>>   at the VBM and/or CBM or close to, then :GAP will be larger than
>>   the band gap from a band structure.
>>
>>   F. Tran
>>
>>   On Wed, 9 Dec 2015, Muhammad Sajjad wrote:
>>
>> Dear AllDoes the command "grep GAP *.scf" gives
>> correct band gap value? as when I found the bottom
>> of conduction band in xmgrace it is higher. (bottom
>> of CB is
>> read correctly by opening the plot in xmgrace and
>> then read the date by editing in text editor).
>>
>> --
>> Kind Regards
>> Muhammad Sajjad
>> Post Doctoral Fellow
>> KAUST, KSA.
>>
>>
>>   ___
>>   Wien mailing list
>>   Wien@zeus.theochem.tuwien.ac.at> Wien@zeus.theochem.tuwien.ac.at>
>>   http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>   SEARCH the MAILING-LIST at:
>>
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>>
>>
>>
>> --
>> Kind Regards
>> Muhammad Sajjad
>> Post Doctoral Fellow
>> KAUST, KSA.
>>
>>
>> ___
>> Wien mailing list
>> Wien@zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>>
>>
>>
>> --
>> Kind Regards
>> Muhammad Sajjad
>> Post Doctoral Fellow
>> KAUST, KSA.
>> ___
>> Wien mailing list
>> Wien@zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>> SEARCH the MAILING-LIST at:
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>
>
>
> --
> Kind Regards
> Muhammad Sajjad
> Post Doctoral Fellow
> KAUST, KSA.
>



-- 
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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Re: [Wien] Issue with different convergence results and QTL-B warnings

[Lyudmila Dobysheva]

09.12.2015 20:57, Michał Wojciechowski wrote:

Currently I’m performing calculations for a chromium magnetic wheel  - 
Cr_8F_8(O_2CH)_16.
J = (E_FM - E_AFM)/36.
Approach 1.
I start with PBE functional from a command line with:
runsp_lapw -i 50 -ec 0.1 -cc 0.001
The calculations converge nicely with no warnings or errors.
I then change the XC functional to B3LYP (option 47 in case.in0 and additional 
case.ineece file)
and run the command:
runsp_lapw -eece -i 50 -ec 0.1 -cc 0.001
The calculations converge nicely with no errors but there is a single warning:
:WARN : QTL-B value eq.  11.12 in Band of energy  -2.28970  ATOM=   27  L=  0
Atom 27 is carbon.
Using -in1new I was able to determine, that using parameter -1.70 instead of 
0.30 resolves the issue.
I then changed entries for all carbon atoms
and continued the calculations. This time I got no warnings and obtain results:
E_FM = -24370.92259156 Ry
E_AFM = -24370.92652933 Ry
J = 1.5 meV
Approach 2.
I started with PBE functional and already modifie energy parameter in case.in1.
After convergence is reached I continue with B3LYP functional. No warnings are 
present and
I obtain the following results:
E_FM = -24370.91735838 Ry
E_AFM = -24370.92522898 Ry
J = 3.0 meV


I am not an expert in B3LYP, so I am writing about only general 
considerations.

The reason may be
1) different execution. For example, you have made, by accident, for the 
final calculation in first case -in1new, in second - usual, without this 
option. Check the executions in dayfile's, :log's, and everywhere where 
this info can be found. And check all parameters. Compare the in-files 
in the whole saved directories.
Though system looks rather symmetric, there are 5 nonequivalent Cr 
atoms. Had you done force relaxation? Is struct files identical in both 
cases? in all four cases?
2) Maybe some parameter doesn't reach convergence, so small variations 
in calculation scheme (starting electron density) gives different 
results. Under suspicion, imho, RKM = 2.0 (as far as I remember, the 
recommendation for H-containing systems is RKM=3), very different RMT

2.40 and 0.83 Bohr for Cr and H, single k point.
3) maybe this exotic scheme of potential gives you really two different 
points? Look in case.scf other parameters, especially magnetic moments 
of Cr's, especially FM states (the difference is largest. For AFM it 
looks for me as not different).
3A) maybe this is a peculiarity of B3LYP scheme, and its iterative 
procedure allows to fix solution in some points that are not real 
minimum. Maybe users with experience with B3LYP can add something about 
this.
3B) Maybe this different solutions are really different minimums due to 
different Cr atoms with differently distributed moments among them.


Offtop:
> J = (E_FM - E_AFM)/36.
Why 36? There is another number of atoms?

Best wishes
Lyudmila Dobysheva
--
Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci.
426001 Izhevsk, ul.Kirova 132
RUSSIA
--
Tel.:7(3412) 432045(office), 722529(Fax)
E-mail: l...@ftiudm.ru, lyuk...@mail.ru (office)
lyuk...@gmail.com (home)
Skype:  lyuka17 (home), lyuka18 (office)
http://ftiudm.ru/content/view/25/103/lang,english/
--
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Re: [Wien] Correct band gap value

[Muhammad Sajjad]

Manually means I opened the band structure in xmgrace then simply clicked
on the CBM and the went to the text editor to read the exact lowest value.
I am simply using Silicon (with 2% strain) and the plot is along W L G X W.

On Thu, Dec 10, 2015 at 10:35 AM,  wrote:

> What does "manually" mean? If it means band structure plotting, then
> probably the VBM and/or CBM is not along the path in the Brillouin zone
> that you chose.
>
> F. Tran
>
>
> On Thu, 10 Dec 2015, Muhammad Sajjad wrote:
>
> I selected 2000 k-points. grep GAP *.scf gives 0.923 eV while manually I
>> found VBM at 0.0 eV and CBM at 1.10023 eV. So which one should be correct?
>>
>> On Thu, Dec 10, 2015 at 12:20 AM,  wrote:
>>   If your k-mesh is not dense enough such that there is no k-point
>>   at the VBM and/or CBM or close to, then :GAP will be larger than
>>   the band gap from a band structure.
>>
>>   F. Tran
>>
>>   On Wed, 9 Dec 2015, Muhammad Sajjad wrote:
>>
>> Dear AllDoes the command "grep GAP *.scf" gives
>> correct band gap value? as when I found the bottom
>> of conduction band in xmgrace it is higher. (bottom
>> of CB is
>> read correctly by opening the plot in xmgrace and
>> then read the date by editing in text editor).
>>
>> --
>> Kind Regards
>> Muhammad Sajjad
>> Post Doctoral Fellow
>> KAUST, KSA.
>>
>>
>>   ___
>>   Wien mailing list
>>   Wien@zeus.theochem.tuwien.ac.at
>>   http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>   SEARCH the MAILING-LIST at:
>>
>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>>
>>
>>
>>
>> --
>> Kind Regards
>> Muhammad Sajjad
>> Post Doctoral Fellow
>> KAUST, KSA.
>>
>>
> ___
> Wien mailing list
> Wien@zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:
> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
>
>


-- 
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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[Wien] msr1a: charged or uncharged supercell?

[Yocefu Hattori]

Dear Wien2k users,

I'm working in a charged supercell and I want to obtain its optical
properties. Should I minimize internal parameters before or after charging
the material?

Thanks,

Yocefu H.
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Re: [Wien] msr1a: charged or uncharged supercell?

[Laurence Marks]

You minimize for the ground state (initial state), and then would invoke
the Born–Oppenheimer approximation

On Thu, Dec 10, 2015 at 2:30 PM, Yocefu Hattori 
wrote:

> Dear Wien2k users,
>
> I'm working in a charged supercell and I want to obtain its optical
> properties. Should I minimize internal parameters before or after charging
> the material?
>
> Thanks,
>
> Yocefu H.
>



-- 
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu
Corrosion in 4D: MURI4D.numis.northwestern.edu
Co-Editor, Acta Cryst A
"Research is to see what everybody else has seen, and to think what nobody
else has thought"
Albert Szent-Gyorgi
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[Wien] Stress values

[Muhammad Sajjad]

Dear All
Can we find stress value in wien2k?

-- 
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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Re: [Wien] Stress values

[Fecher, Gerhard]

Please read and understand the literature on elastic constants and their 
calculation by ab-initio calculations

afterwards you may try the programs found in the "Unsupported software goodies" 
section of Wien2k, or the ones that come with Wien2k


Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Muhammad Sajjad 
[sajja...@gmail.com]
Gesendet: Donnerstag, 10. Dezember 2015 11:48
An: wien
Betreff: [Wien] Stress values

Dear All
Can we find stress value in wien2k?

--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.
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Re: [Wien] Correct band gap value

[Fecher, Gerhard]

It seems your knowledge on -- just to name a few -- crystal structures, real 
space, Brillouin zone, symmetry, space groups, and other basics is not that 
high.
Those things, however, you need to know to understand what you are doing in the 
calculations.

F means you have a face centered cell but does not tell you much more, what do 
you mean why the number of symmetry opetrations changes ?

If you distort a cubic lattice (x,y,z  are equal) in one direction, say along 
z, you end up in a tetragonal structure and x (or y) and z are not longer the 
same.
That is the [001], [001] directions are not longer the same, and also [110] and 
[101] are not the same anymore, etc.

I realy suggest that you learn much more about crystal structures before you 
start to calculate something

The forum is not good for teaching textbook knowledge

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: wien-boun...@zeus.theochem.tuwien.ac.at 
[wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Muhammad Sajjad 
[sajja...@gmail.com]
Gesendet: Donnerstag, 10. Dezember 2015 10:05
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] Correct band gap value

It looks same (in shape). I selected lattice type F and applied strain. Only 
symmetry operations reduce to 16 from 48 (for bulk Si). Also I kept the volume 
constant for every value of strain.

On Thu, Dec 10, 2015 at 11:29 AM, Fecher, Gerhard 
> wrote:
Did you check how the Brillouin zone looks like in the tetragonal case after 
you applied the strain ?
Is your k-path that you used for the xmgrace plot the one that you like to have 
to find the correct gap ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: 
wien-boun...@zeus.theochem.tuwien.ac.at
 
[wien-boun...@zeus.theochem.tuwien.ac.at]
 im Auftrag von Muhammad Sajjad [sajja...@gmail.com]
Gesendet: Donnerstag, 10. Dezember 2015 09:19
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] Correct band gap value

Manually means I opened the band structure in xmgrace then simply clicked on 
the CBM and the went to the text editor to read the exact lowest value. I am 
simply using Silicon (with 2% strain) and the plot is along W L G X W.

On Thu, Dec 10, 2015 at 10:35 AM, 
>>
 wrote:
What does "manually" mean? If it means band structure plotting, then
probably the VBM and/or CBM is not along the path in the Brillouin zone
that you chose.

F. Tran


On Thu, 10 Dec 2015, Muhammad Sajjad wrote:

I selected 2000 k-points. grep GAP *.scf gives 0.923 eV while manually I
found VBM at 0.0 eV and CBM at 1.10023 eV. So which one should be correct?

On Thu, Dec 10, 2015 at 12:20 AM, 
>>
 wrote:
  If your k-mesh is not dense enough such that there is no k-point
  at the VBM and/or CBM or close to, then :GAP will be larger than
  the band gap from a band structure.

  F. Tran

  On Wed, 9 Dec 2015, Muhammad Sajjad wrote:

Dear AllDoes the command "grep GAP *.scf" gives
correct band gap value? as when I found the bottom
of conduction band in xmgrace it is higher. (bottom
of CB is
read correctly by opening the plot in xmgrace and
then read the date by editing in text editor).

--
Kind Regards
Muhammad Sajjad
Post Doctoral Fellow
KAUST, KSA.


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--
Kind Regards
Muhammad 

Re: [Wien] Issue with different convergence results and QTL-B warnings

[Peter Blaha]

a) Interesting choice of RMTs, but probably not optimal. You should use 
setrmt as basis for your choice. It would reduce RMT(H) (0.6) and 
increase R(C) a bit, but still make Oxygen 15% larger than C. In 
particular the F-spheres are much too small at present. I'd use 2.0/1.6 
or 1.9/1.7 for Cr and F spheres.


RKMax=2.0 with your spheres is VERY small and I'd NOT trust any results 
with this setup. With my spheres you need RKMax 2.5-3.0.


b) I agree, for such molecular materials, our default E-parameters might 
not be optimal and problems for all the small spheres F, O and C may 
appear. Even WITHOUT QTL-B warnings, the E-parameter of F and O may not 
be optimal !
As mentioned many times on the mailinglist, the way to check this is 
looking at case.scf1 and case.scf2. It is not enough just to look at 
case.in1c, as these numbers will be changed automatically in lapw1:

0.3   --->  EF-(or+) 0.2
-0.71  0.002 ---> it tries a search, but for small spheres it probably 
will actually use -0.71 because it does not find E-top


You probably find in case.scf1 that the two C-s (l=0) E-parameter are 
very close to each other (using the default input)!


a) Locate the fermi energy !
b) locate the mean energies of C-2s (and O-2s and F-2s) by looking in 
case.scf2  (:EPL and :EPH)
c) change the FIRST line for l=0 of all the small atoms to this E-value 
in case.in1c (for C this might be -1.7 in your case). Leave the 0.30 
untouched, as this will be automatically adjusted according to EF. 
Repeat this for ALL "small" atoms (except for H).


-
Otherwise:  compare the magnetic states of your calculations. I'm rather 
surprised that also the FM solutions are different, but it could well 
be. We know that all "orbital-dependent" potentials (like LDA+U or 
hybrid-DFT) depend a lot on the starting electronic structure.

Compare the :MMI and :QTL values.

If your calculations are ok, then the total energy is a good measure, 
which state is most favorable.



On 12/09/2015 05:57 PM, Michał Wojciechowski wrote:

Dear Wien2k users!
Currently I’m performing calculations for a chromium magnetic wheel - 
Cr_8F_8(O_2CH)_16. While I intend to get various quantities the primary one is 
magnetic interaction parameter J between chromium ions. To that end I require 
energies of two spin configurations - ferromagnetic (E_FM) and 
antiferromagnetic (E_AFM) - since J = (E_FM - E_AFM)/36.
The case file is attached. I’m using RKM = 2.0 (NMATMAX = 50 000, so RKM is 
unreduced), RMT = 2.40, 1.20, 1.24, 1.00 and 0.83 Bohr for Cr, F, O, C and H, 
respectively, single k point since it is a molecule. Remaining parameters are 
default or as suggested by the program. I use two approaches.
Approach 1.
I start with PBE functional from a command line with:
runsp_lapw -i 50 -ec 0.1 -cc 0.001
The calculations converge nicely with no warnings or errors. I then change the 
XC functional to B3LYP (option 47 in case.in0 and additional case.ineece file) 
and run the command:
runsp_lapw -eece -i 50 -ec 0.1 -cc 0.001
The calculations converge nicely with no errors but there is a single warning:
:WARN : QTL-B value eq.  11.12 in Band of energy  -2.28970  ATOM=   27  L=  0
Atom 27 is carbon. The case.in1 entry for this atom is
   0.303  0  (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
  0   -0.71  0.002 CONT 1
  00.30  0.000 CONT 1
  10.30  0.000 CONT 1
Using -in1new I was able to determine, that using parameter -1.70 instead of 
0.30 resolves the issue. I then changed entries for all carbon atoms to
   0.303  0  (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
  0   -0.71  0.002 CONT 1
  0   -1.70  0.000 CONT 1
  10.30  0.000 CONT 1
and continued the calculations. This time I got no warnings and obtain results:
E_FM = -24370.92259156 Ry
E_AFM = -24370.92652933 Ry
J = 1.5 meV
Approach 2.
I starte with PBE functional and already modifie energy parameter in case.in1. 
After convergence is reached I continue with B3LYP functional. No warnings are 
present and I obtain the following results:
E_FM = -24370.91735838 Ry
E_AFM = -24370.92522898 Ry
J = 3.0 meV
So the issue is why are there such big differences? Which quantities should I 
check to determine the source of these discrepancies?
I am running Wien version 13.1 on a one, single processor, multi-core Intel 
Xeon machine with openSUSE 13.1 operating system. Programs were build with 
Intel compilers and math libraries (Intel Composer 2013 SP1) and OpenMPI 1.6.5.

Best Regards

--
Michał Wojciechowski
PHD student at Institute of Physics
Department of Physics and Astronomy
University of Zielona Góra, Poland



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--